Monday, January 27, 2014


Also in this week's C&EN's letters to the editor, the magic of chemical engineering knowledge to provide people with job skills: 
An Idea For Unemployed Chemists 
Have you ever wondered why chemical engineers fresh out of school, or at any level for that matter, are offered higher salaries than chemists? Or, why is unemployment for chemists a more likely circumstance than it is for chemical engineers? Both majors take the same organic and physical chemistry classes. We all love the beautiful science of chemistry, so why this startling difference? 
Linda Wang’s recent article, “Hired … for Now,” highlights eight career-related benefits from the American Chemical Society to aid unemployed members (C&EN, Dec. 2, 2013, page 33). Here’s another: Any students majoring in chemistry as well as any unemployed chemists would find their career enhanced by even a brief exposure to chemical engineering. 
For an introduction to chemical engineering, chemists at any level should consider enrolling in two gatekeeper courses in the chemical engineering curriculum: “Material Balances” and “Energy Balances.” No need to fret about that great demon for many nonengineering students—math—for in these two courses the most advanced math required is arithmetic. Rather, what is required is detailed analytical thinking and practice in application to many different sorts of problems. Consider this one: Your car runs on gasoline with 10% excess air having a relative humidity of 30%. Calculate the quantitative analysis of the exhaust from the tailpipe. 
One can easily imagine all sorts of similar complex problems to solve. They seem trivial in principle, but they are tedious in practice. So be prepared. Chemical engineering courses are hard—no auditing. After this taste, one might try a course that covers thermodynamics or perhaps heat transfer. But now advanced math becomes essential. 
Henry McGee
Richmond, Va.
Personally, I would attribute the higher salaries and lower unemployment of chemical engineers to the fact that it's a smaller, more specialized field, with higher barriers to entry in terms of schooling (harder to set up a College of Engineering than a College of Science, probably, and there are likely fewer of them) and licensing requirements for chemical engineers. But that's my Economics 101 view of the world, and I'm probably missing something.

[Fans of logical fallacies -- is Dr. McGee's "any unemployed chemists would find their career enhanced..." statement an example of "question begging"? I don't think so, but I can't find the correct logical fallacy.]

I find it amusing that Professor McGee believes that it is the higher amounts of mathematical training that results in chemical engineering being more remunerative. Well, maybe; it certainly results in yet another barrier-to-entry for non-mathematically inclined folks. But somehow I think there are other factors in play. 


  1. The chemistry students take just as many much math courses as the Chem Eng majors at my university. The nature of the courses are much different however. Chem students will apply "math" in thermodynamics, quantum and spectroscopy, whereas chem eng will focus on subjects mass and heat transfer. The advanced math courses we take are multivariate calculus and ordinary differential equations. The base math classes for both majors are Cal I and II, linear algebra and statistics. Chem students interested in theory will often take extra math courses on top of this. As you say, the difference in salaries are probably due to relative demand, and the fact that chem eng is an accredited program and you can become a professional engineer afterwards, which is valued due to some regulatory practices.

  2. I'm an organic chemist and the highest math courses I took were Calculus III, Linear Algebra and Differential Equations, although I forgot all of that just like I forgot my nukelar physics course that I took for fun. What the hell do the engineers take above that? If I knew at the time, I would have probably taken that as I got pretty good grades in all those higher math courses. Now I'd probably fail.

  3. I would substitute "learn math" for "learn programming" (or at the very least learn programming to solve diff eq or something). In physical or analytical chemistry at higher levels, it's pretty much required to know how to do some kind of programming for statistical analysis, signal processing, kinetics modeling, etc. And then you at least have some skill that has application outside of chemistry.

  4. Training on specialized, commercial software is one key reason ChemE graduates command higher salaries. All the math is hidden under the hood. How much do you really need to know?

  5. I've always advocated that chemists should take some ChemEng course, not what was recommend above, but fluid mechanics and heat transfer. I have seen countless situations in which chemists would have been better for knowing these areas, but what really, really puzzles me is how there seems to be this almost smug pride at being ignorant of the subjects, Or maybe it is blissful ignorance. Or something similar. I've yet to ever see a chemist expand their technical knowledge by studying heat transfer.

    I know a student who right now is trying to decide between Chem and ChemEng. Both me and another ChemE have been telling him to at least start the ChemEng sequence. We both agree that knowing fluid mechanics and heat transfer will never ever hurt him if he decides to go the chemistry route.

    And by the way, very few if any ChemEngs ever get licensed, so that isn't a contributing factor to income differences. (I can't explain what is.)

    1. John, what texts would you suggest (have I asked you this before? if so, I'm sorry.) for fluid mechanics and heat transfer?

    2. Fluid Mechanics, 7th ed., Frank White.
      Principles of Heat and Mass Transfer, 7th ed., Incropera.

      Those are the two texts used at University of Toronto.

    3. CJ,

      I liked "Basic Heat Transfer" by Kreith and Black when I used it 30 years ago. The electrical analogies really helped.

      Fluids? I don't know. I had "Fluid Mechanics" by White, which someone else has already suggested. It was ok, but since I quickly went into non-Newtonian fluids after that, I never really felt an urge to look for something better.

      I would stay away from BSL (someone suggested that) even though it is part of the Canon. It's too ChemEng oriented in my mind. I'm suggesting that chemists learn somethings from the ChemEng curriculum, not become ChemEng's.

      (And as you can see, I can freely access your comment section again. Don't ask me why.)

  6. The explanation for the salary difference was explained to me in terms of proximity to goods for sale. A chemist (seldom a BS chemist) might invent something, but a chemical engineer can produce a tank car of the material to sell. The chemist will have a more tangible connection to costs than to sales.The Chem E will have much closer tie to the goods for sale. An even higher salary might go to those that make the sale.

    I agree with John that knowing a little bit of heat transfer and fluid mechanics is helpful. They were interesting and helped me choose chemistry.

    1. PJ, what texts would you suggest for fluid mechanics and heat transfer?

    2. Sorry, no texts to recommend. Just too long ago.

    3. Clear evidence that the Engineers Are Hoarding Their Knowledge!

      (just kidding, thanks for your response.)

    4. Transport Phenomena by Bird, Stewart and Lightfoot,or BSL, is the classic ChemE text for fluid mechanics, heat transfer and mass transfer. But it may not be a good entry level text because it, and the subject as a whole, is math-intensive.

    5. I found Bergman, Lavine, Incropera and DeWitt fully comprehensible after Calc I and II but before taking Differential Equations. As long as you limit the transport to 1D the math isn't particularly challenging, it's just a matter of being able to set up appropriate boundary conditions. Beyond 1D it's time to bring in the computer simulations.

  7. I earned a PhD in materials chemistry and am currently working towards a MS in mechanical engineering. I've observed many differences between the LAS and engineering programs. Both socially and academically. From my time in LAS studying chemistry, everything was much more theoretical while engineering has felt more grounded in the theme, "Here's how to solve/model this real world system." As a chemist I learned about heat transfer while in PChem/Thermo, but I learned significantly more about how to model systems in Heat Transfer. Heat transfer gave me many more tools/equations to understand a given system. Going further, chemists all take two semesters of physics. These physics classes focused more on model systems such as simple projectile motion. Taking dynamics while studying MechE teaches much more useful methods to approach a system such as normal and tangential coordinate systems. Also, more real world systems were covered when covering relative motion analysis.

    In terms of employability, I started the MechE program due to a lack of opportunities for people holding degrees that only say chemistry. I think PJ is along the right line of thinking that engineers are more closely associated with revenue/profit generation, where as chemists are more of a cost center that may or may not yield a profit in the future. Beyond the economics, I think employment opportunities come down to discrimination/stereotyping by HR. For most HR types, a chemist sits at a bench and runs reactions, while engineers sit at a desk and solve the bigger problems.

  8. I did both math and chemistry - and am long-term unemployed.

  9. I talk to my chemical engineer friend who is employed in industry sometimes. Although he has a masters degree in chemical engineering, he tells me that the high level of math/physics/chemistry helped him in his education. At work, he says the most important thing is identify a problem and solve it. Or at least know how to approach it. He told me a few stories to give some examples. For example, they had a really large reaction vessel and the reaction didn't proceed as they expected. Took them some time to figure out that not all the solution is stirred at the same rate (they needed extra stirrers in the vessel etc) and also the walls of the vessel (the heating mantle was below the level of the solution etc.) affected the reaction and gave unwanted products etc. Obviously, when it comes to solve problems thermodynamics and heat transfer helps him a lot. But, as long as you know where to look for information, you are OK I think.

    By the way here is a ~200 page free Fluid Mechanics lecture notes from a Physics professor at Uni. of Texas at Austin.

  10. CJ, Licensing requirements for chemical engineers are basically nil for the vast majority of working chemical engineers. There *is* an option to receive certification as a "professional engineer" or "PE", but, for a variety of reasons, very few chose to obtain this credential.

    I'm not sure whether it really is easier to set up a school of science than a school of engineering, but who knows -- you might be onto something there.

    I suspect that the focus on "detailed analytical thinking and practice in application to many different sorts of problems" that letter-writer McGee attributes to chemical engineering is true, but really only a value-add to the bottom tier of students. I mean, can you imagine a top 10% or even top 30% graduate from a top 50 *chemistry* department not knowing how to do the humid rich fuel-burning calculation? I figure every good graduating B.S. chemist -- as well as every good B.S.-level chemical engineer -- knows how to solve the problem. It's not rocket science, and basic knowledge of stoichiometry is all that you need.

    The same probably can't be said for the bottom tier of students. Among the bottom tier, the training for chemical engineers probably means that many more chemical engineers know how to solve the problem than chemists.

    Further suppose that employers are unable to precisely determine applicant ability from interviews. So even though no employer is interested in a bottom-tier student, given that they can't be sure what tier someone is in, they benefit from preferring the chemical engineer.

    Thus, even though I think the chemical engineering credential acts mainly as a floor on maximum possible incompetence rather than a signal of true ability, in the presence of imperfect hiring information it winds up benefiting all credential-holders, not just the less competent.